Lock for fire plug caps



DCC. 22, 1931. w. MODRA 1,837,881

LOCK FOR FIRE PLUG CAPS Filed Jan. 17, 1931 2 Sheets-Sheet l /fmnllmm L? 22252K Dec, 22, 1931. w MODRA 1,837,881

LOCK FOR FIRE PLUG CAPS Filed Jan. 17, 1931 2 Sheets-Sheet 2 .I Z 5 4 @L .6. l, A

W/L L /HM Mone/v.

5y WQLM'M Patented Dec. 22, 1931 g entre!) STATES testati WILLIAM MCDBA., F ST'. LOUIS, MISSOURI Loox non. FIRE PLUG CAPs Application led January 17, 1931. Serial No. 509,380.

My invention has relation to improvements in loch-ing mechanism for fire-plug caps and it consists in the novel features of construction more fully set forth in the specification and pointed out in the claims.

The invention is directed particularly to a fireplug cap that is hinged to the plug and has embodied in, or associated with the hinge, a locking mechanism that will prevent the removing of the cap unless a key is first applied to the hinge for releasing the lock.

The object of the invention is to provide a tire-plug cap that is primarily connected to the plug so as to be always available and in v position for instant application; a further object of the invention is to provide a lock in association with a hinge, so that it will be impossible for meddlesome persons to remove the lire-plug cap, thereby protecting the plug f nozzle against tampering by street urchins.

A still further object of the invention is to provide a loclr that may be housed within the hinge for protection, and one that is simple and positive in its operation; further and other advantages will be better apparent from a detailed description of the invention in connection with the accompanying drawin which:

Figure l is a side elevation of a nre-plug f with my improved cap and lock applied thereto; Fig. 2 is a horizontal crosssection taken on the line 2 2 of Fig. 1 with part of the plug broken away and the plug nozzle and cap shown in elevation; Fig. 3 is a front elevation of the cap hinge members, parts thereof being broken away to show the hinge pin in elevation; Fig. l is a cross-sectional view through the hinge pin taken on the line 4 4 of Fig. 3; Fig. 5 is a cross-sectional detail taken on the line 5-5 of Fig. 3; Fig. 6 is a cross-sectional detail taken on the line 6-6 of Fig. 3 showing the hinge locked to prevent removal of the cap from the plug nozzle; Fig. 7 is a section similar to Fig. 6 showing then hinge lock released to permit rotation of the cap about the hinge pin; Fig. 8 is a section similar to that shown in Fig. 7 with the cap rotated to open position; and Fig. 9 is a view showing a band clamped to the fire-plug nozzlc to permit the application of my improved cap and lock to old tire-plugs not otherwise i equipped therefor.

Referring to the drawings F represents a fire-plug of conventional design, having the customary water discharge spout S, terminating in a threaded fiange f adapted to receive the hose vof the pumping engine (not shown). Obviously, the threads t, over which the hose fitting is screwed, must be protected against injury and the spout S must also be closed as a protective measure by a suitable cap C. Heretofore the fire-plug 4caps have been provided with threadsiso that they could be screwed onto the threads t of the spout S, but no means was provided for preventing the removal of the caps by meddlers.- My invention contemplates a cap having a flange l' provided with a smooth inner surface, of a diameter sufficiently greater than the diameter of liange f to enable the cap to be easily lifted from the liange or disposed over the flange. instead of the cap C being screw-threaded to the flange f, it is primarily'attached to the plug P by means of a hinge H comprising outer hinge members 2, 2 projecting laterallyfrom the spout S and a hinge member 3 projecting laterally from the capC. A hinge pin comprising complementary sections 4:, 4 traverses the hinge members 2,2 and 3 and `forms the element about which the cap C swings. f It will be observed that the hinge H is disposed beyond the plane of shoulder formi-ng the base of threads t so that when the cap C is swung to a position opposite its closed position, the space above the shoulder 5 will be cleared of all obstruction 'to permit the attachment of the hose fitting to threaded flange f.

The locking mechanism is housed within hinge pin sections 4, t and hinge member 3 of the cap, and may be described as follows: Hinge sections 4, 4. are of course cylindricaland are shouldered together along a medial line a. Said sections are each provided with an axial bore which, when the sections areassembled, forms a continuous bearing 6 for a cam shaft 'which is mounted in said sections. The shaft 7-has a cam 8 formedk integrally with it intermediate its ends, said cam` being adapted to operate in the recess 9 formed to receive it in hinge section 4. The shaft 7 terminates at one end in a square extremity 7 over which is disposed a polygonal collarrlO secured in place by a pin 11, said collar forming a removable head for the application of a wrench by means of which the shaft 7 may be'rotated to actuate the lock, which will be apparent hereinafter. A. key 12 is provided for locking the hinge member 3 to the hinge pin sections 4, 4 and holding the cap C in closed position over the flange f. The key 12 is housed in a longitudinally disposed slot 13 formed in hinge member 3 and is adapted to be received in a longitudinally disposed groove 14 formed in hinge sections 4, 4 and intersecting the recess 9 in section 4. When the cam 8 is rotated to the left as far as it will go, (Fig. 6) its cam surface 8 will be in a position that will allow the key 12 to be forced downwardly into groove 14 under the pressure exerted by springs 15, 15 disposed in the outerv part of slots 13 and held in place` by screw plugs 16,16.V Vhen the shaft 7 is rotated vin the direction of the arrow (Fig. 7) the cam surface will ride over the'nose of key 12 and force the same out of its depression 14 until the key rests upon the outer surface 8'of the cam which coincides with the outer surface of hinge pin sections 4, 4. When the key 12 is thus resting on the cam surface 8" any further movement of the camis revented by its engagement with thewall 17 of recess 9. It is obvious that when the key isv 35 thus free from the groove 14, the hinge member 3, and of course the cap C, may befrotated on the hinge pin. During this rotation the key 12 will ride over the outer surface of said hinge pin (Fig. 8). When the cap C is again rotated to closed position, the key 12 rides over the hinge pin in the opposite direction, coming to rest opposite to depression 14 whereupon a slight rotation of the shaft 7 by the application of the wrench W willrwithdraw the cam 8 from said key and allow it to be forced into depression 14 under the pressure of springs 15, 15.

In order that the hinge Vpin may be firmly fiXedin the members 2, 2, and 3, the section 4 has its outer end 18 square so as to fit into square opening 19 in Vhinge member 2 and the outer end of section 4 is traversed l member projecting from them, a device such as the band 23 is resorted to to provide the means to which the cap is hinged.

Having described my invention I claim:

In combination with a fire-plug having a discharge nozzle, a cap adapted to tit over said nozzle, a hinge connecting said cap to the Vplug, vsaid hinge comprising cooperating lugs on the plug and cap and a hinge pin traversing the lugs, a movable key arranged to lock one of the lugs to the hinge pin, and a cam shaft mounted in the hinge pin and adapted to actuate the key to release said lug from the hinge pin.

In testimony vwhereof I hereunto afIiX my signature. Y

VILLIAM MODRA.

by an opening 2O to receive a locking pin 21 which also traverses alining openings 22, 22 in hinge members 2. Thus the sections 4A and 4 are securely held against longitudinal dis-v placement in the hinge members, as well as beinG'he-ld against rotation in the members 2'20 b In Fig. 9 I show a dotted fragment-,of an i 'oldn style of vfire-plug, around the spout S of Y which maybeclamped a band A23 carry` ingA hinge lugs 24, 24 for receiving the hingelug 3 and hinge pin sections 4, 4*. Since the old style of plugs have no hinge 

